The present invention relates to a fuel-air-mixture-forming device for an internal combustion engine having a nozzle body of rotational symmetry which together with a throttle body of rotational symmetry which, is displaceable within the nozzle body, forms a convergent-divergent nozzle which debouches into an intake pipe of the internal combustion engine. The device includes a fuel-air slot which surrounds the convergent-divergent nozzle and debouches via a circumferential slot opening into the nozzle. Fuel mixed with air is injected into the nozzle from the slot opening in a direction approximately transverse to the direction of the main air mass flow.
Such a mixture-forming device is known from German patent document 36 43 882 Al. In it, the air mass flow is controlled by means of the throttle body, a greater or lesser vacuum being established in the intake tube and thus at the wall of the throttle body, depending on the state of load of the engine. This vacuum produces on the throttle body closing forces, which must be applied upon the opening of the throttle body.